Zeiss 16-35 is very good. But seeing that you have 11-16 may be you'll be better served with sony 16-50. Not sure if you actually need FF lenses.

And the 18-35mm F/1.8 will cover that range too with a larger aperture. Granted the 16-35 is full frame, but not a range in full frame I see myself using very much if I go to a Full Frame camera in the future

16-17 is a fair amount of difference at wide angles. But I guess your tokina will cover it fairly for you.

Right now everything that is not wide angle is my 'weakest link' lol. My telephoto is beercan, my primes are minolta 28mm f2.8 and 50mm f1.7. Thats pretty much it lol. Tbh, it will remain this way for a while for me. I am sure I can still manage to gather nice pictures with these.

If you read reviews especially Kurt munger the tamron 28-75 f2.8 seems to give very good IQ comparable to zeiss. So may be thats an option for you? The sigma 18-35 will cover the missing range.

I don't really consider the Tamron 28-75 F/2.8 (or the Sony for that matter) a step up enough from the Sigma consider going to it in place of my Sigma. The Tamron's focusing is screw driven while the Sony's is the slower, noisier SAM (when compared to SSM and HSM). I also feel for this zoom range that 28mm is a bit too long for use on a crop sensor (which is around 42mm). 24mm as the wide end for this zoom range (equivalent to around 36mm) is about as long as I would want to go. It is a little bit sharper at F/2.8, but they tend to level out pretty quickly a little beyond that. I don't feel the difference is worth sacrificing the HSM focusing and the wider focal length on the wide end of the zoom.

Tamron is also really cheap for excellent quality. Its one of those lenses I would buy anyway as it costs almost nothing in grand scheme of things. Its going for £200 used atm here. I am sure I can haggle it down to £175 at least.

If you don't mind up-ing the ISO 24-105 f4 will give you a much better range. I am just wondering if sony will release one too. Also I wonder how good the sony/tamron 24-105 f3.5-4.5 is. I am not too bothered about the 0.5 difference.

I like how we have turned a discussion about camera bag into a lens discussion lol.